This specification relates to data processing and search services.
The Internet provides access to a wide variety of resources such as images, video or audio files, web pages for particular subjects, book articles, or news articles. A search system can identify resources in response to a text query that includes one or more search terms or phrases or in response to a non-text query, such as an audio query, video query, or image query. The search system ranks the resources based, at least in part, on their relevance to the query and provides search results that respectively reference (e.g., link to) the identified resources. The search results are typically ordered for viewing according to the rank.
Some content providers may respond to a request for a resource differently depending on the nature of the device that requests it and the circumstances. For example, some content providers may provide one version of a web page to most browsers under the assumption that a full-sized display, such as a desktop monitor, will be used to view the webpage. Another version of the web page optimized for a much smaller display may be provided when the content provider determines that a mobile device is requesting the resource. Furthermore, some websites may redirect to a login page for any user that is visiting the website for the first time, or may automatically redirect external traffic to the home page. Websites may also serve resources based on the location or language of the user, as well as other demographic data.